Toward an ecological aesthetics: music as emergence

In this article we intend to suggest some ecological based principles to support the possibility of develop an ecological aesthetics. We consider that an ecological aesthetics is founded in concepts as “direct perception”, “acquisition of affordances and invariants”, “embodied embedded perception” and so on. Here we will purpose that can be possible explain especially soundscape music perception in terms of direct perception, working with perception of first hand (in a Gibsonian sense). We will present notions as embedded sound, detection of sonic affordances and invariants, and at the end we purpose an experience with perception/action paradigm to make soundscape music as emergence of a self-organized system

Newtonian Perturbations on Models with Matter Creation

Creation of Cold Dark Matter (CCDM) can macroscopically be described by a negative pressure, and, therefore, the mechanism is capable to accelerate the Universe, without the need of an additional dark energy component. In this framework we discuss the evolution of perturbations by considering a Neo-Newtonian approach where, unlike in the standard Newtonian cosmology, the fluid pressure is taken into account even in the homogeneous and isotropic background equations (Lima, Zanchin and Brandenberger, MNRAS {\bf 291}, L1, 1997). The evolution of the density contrast is calculated in the linear approximation and compared to the one predicted by the $\Lambda$CDM model. The difference between the CCDM and $\Lambda$CDM predictions at the perturbative level is quantified by using three different statistical methods, namely: a simple $\chi^{2}$-analysis in the relevant space parameter, a Bayesian statistical inference, and, finally, a Kolmogorov-Smirnov test. We find that under certain circumstances the CCDM scenario analysed here predicts an overall dynamics (including Hubble flow and matter fluctuation field) which fully recovers that of the traditional cosmic concordance model. Our basic conclusion is that such a reduction of the dark sector provides a viable alternative description to the accelerating $\Lambda$CDM cosmology.Comment: Physical Review D in press, 10 pages, 4 figure

Roughness exponents and grain shapes

In surfaces with grainy features, the local roughness $w$ shows a crossover at a characteristic length $r_c$, with roughness exponent changing from $\alpha_1\approx 1$ to a smaller $\alpha_2$. The grain shape, the choice of $w$ or height-height correlation function (HHCF) $C$, and the procedure to calculate root mean-square averages are shown to have remarkable effects on $\alpha_1$. With grains of pyramidal shape, $\alpha_1$ can be as low as 0.71, which is much lower than the previous prediction 0.85 for rounded grains. The same crossover is observed in the HHCF, but with initial exponent $\chi_1\approx 0.5$ for flat grains, while for some conical grains it may increase to $\chi_1\approx 0.7$. The universality class of the growth process determines the exponents $\alpha_2=\chi_2$ after the crossover, but has no effect on the initial exponents $\alpha_1$ and $\chi_1$, supporting the geometric interpretation of their values. For all grain shapes and different definitions of surface roughness or HHCF, we still observe that the crossover length $r_c$ is an accurate estimate of the grain size. The exponents obtained in several recent experimental works on different materials are explained by those models, with some surface images qualitatively similar to our model films.Comment: 7 pages, 6 figures and 2 table